Dan,
IMO for zooms the petal style is probably the best option as they give greater flare protection at the top and bottom. That is not to say that a rubber hood will have no benefit. I use a round rubber hood on my 50mm and 55mm micro lens, and a round metal hood on my 28 mm lens, and my 28-105 and 80-200 have flared round hoods. So the ' petal style ' is not an absolute essential.
If you look at a rubber hood make sure that it does not give vignetting at the 70mm end of your zoom. Easily checked in the shop. I have passed on a collapsible rubber style to Foxy Bob and its shape would certainly have satisfied me if I had your lens. In that case I would only have extended it in rare occasions where flare may be a problem at the 200-300mm end, otherwise leaving it in the collapsed position.
Don ( lens hoods in all shapes & styles )
